1. Field of the Invention
The present invention relates to a portable or cordless electronic apparatus designed to operate based on the electric power supplied from a battery.
2. Description of the Prior Art
Ones often employ handy terminals when they intend to conduct inventory management or suppliance of products in shops and stores. Any suitable software program is installed in the respective handy terminals for realizing the inventory management or suppliance of products. A controller unit including a primary CPU (central processing unit) is incorporated within the enclosure of the handy terminal. The primary CPU implements the software program in the handy terminal. The primary CPU usually operates based on the electric power supplied from a secondary battery coupled to the handy terminal.
In general, the instructions from the software program induces the storing process of data in the handy terminal. If the supply of the electric power is somehow terminated during the operation of the primary CPU, because of less electric power remaining in the battery, for example, the primary CPU is forced to discontinue the operation without conducting the storing process of data. The data may be lost and cannot be recovered. If the electric power remaining in the battery can be monitored, the primary CPU is allowed to conduct the storing process of the input data prior to termination of the electric power from the battery. The data can be prevented from being lost.
A so-called intelligent battery is proposed in the technical field of a portable electronic apparatus. The intelligent battery includes a dedicated CPU and a secondary battery. The dedicated CPU is designed to obtain the information on the status of the battery, such as the remaining electric power in the battery, the voltage level of the output electric power, and the like. A battery information signal specifying the status of the battery is supplied to the primary CPU in the controller unit of the portable electronic apparatus through a communication path, such as a serial interface, established in parallel with a path for the electric power. The primary CPU in the controller unit is allowed to easily monitor the amount of the electric power remaining in the battery. The primary CPU is thus allowed to reliably conduct the storing process of data prior to the exhaustion of the electric power in the battery.
Assume that any deficiency takes place in the battery information signal, due to a defect of the interface for exchanging the battery information signal, for example. The primary CPU of the controller unit cannot monitor anymore the status of the battery or the remaining electric power in the battery. In this case, the portable electronic apparatus may preferably be turned off, subsequent to the storing process of data, immediately after the deficiency has been detected. On the other hand, even in the case where any deficiency is detected in the battery information signal, the electric power of the appropriate voltage level may be supplied to the controller unit of the portable electronic apparatus from the battery. It is very convenient to the user to defer the switch-off of the portable electronic apparatus until the user finishes a series of related operations in the portable electronic apparatus.
It is accordingly an object of the present invention to provide a battery management circuit capable of managing an intelligent battery, possibly without interrupting a series of related operations, even when any deficiency is found in a battery information signal.
According to the present invention, there is provided a battery management circuit comprising: a communication circuit receiving a battery information signal specifying a status of a battery; a voltage detector circuit detecting a voltage level of an electric power from the battery; and a battery controlling circuit reading out the voltage level detected at the voltage detector circuit when a defect is detected in the battery information signal.
The battery management circuit allows the communication circuit to communicate with a dedicated CPU (central processing unit) of an intelligent battery. The communication circuit serves to obtain a battery information signal from the dedicated CPU. The battery controlling circuit is allowed to control the supply of the electric power from the intelligent battery in view of the battery information, such as the electric power remaining in the battery, the voltage level of the supplied electric power, and the like. On the other hand, when a defect or deficiency is found in the battery information signal, the battery controlling circuit switches over the supply and cutoff of the electric power based on the voltage level detected at the voltage detector circuit. In this manner, the supply of the electric power can be controlled without the battery information signal. Even when the defect is found in the battery information signal, the supply of the electric power can be maintained as long as the voltage level is normal. The interruption of the operations can be deferred.
The battery controlling circuit may output an alarm signal in response to detection of the defect in the battery management circuit. Any alarm sound or display can be generated based on the alarm signal for specifying the defect of the battery information signal. Even when an apparatus receiving the electric power keeps operating in a normal manner, the user of the apparatus is reliably informed of the defect of the battery information signal. The user may cut out the supply of the electric power or turn off the apparatus at a subsequent break of related operations. The intelligent battery may thereafter be replaced with a full-charged one, or be fixed.
The aforementioned battery management circuit may be utilized in any types of electronic apparatuses, including a portable electronic apparatus such as a handy terminal, a notebook or hand-held personal computer, and the like, which are designed to operate based on the electric power supplied from an intelligent battery.